351W acting up

[blk88lx]

hey all, I'm having problems w/my GT.

1st, here's my combo:
Stock 5.8W, GT-40 lower, Cobra upper. 24LBS injectors, Adjustable pressure regulator, 155 LPS Fuel pump. Computer is stock 93 HO, pollution control is hooked up.

Heres what it's doing. I've had this set up in the car for about a year now. At low speeds 35 and below the car will buck. When I down shift it sounds like a big block, rough (sounds cool but not right). It pull hard, and runs great at high speed, car has lots of power.

Here's what Ive done (or had done). Vaccum is good, injectors seem good, alternator has been upgraded to a 94 and up, it's fine. Messing w/the timing doesn't help.

Any ideas? I have a freind who is a mechanic who said it seems lean at mid-range but he cant isolate the problem.